The invention relates to electrical circuit arrangements and more particularly to electrical signal processing arrangements. One such circuit arrangement to which the invention relates is a circuit arrangement for producing an output representative of the root mean square (RMS) value of an electrical input signal, and another such circuit arrangement to which the invention relates is for multiplying electrical signals together.
Electrical circuit arrangements for producing an output representative of the RMS value of an input signal are known. Such known forms of circuit arrangement may comprise various forms in which a squaring circuit receives an input signal and squares it, an averaging circuit then produces an average signal proportional to the sum of the squared signal, and a square root circuit then takes the square root of the average signal to produce the required RMS output.
Such circuit arrangements often have application in high precision measurements and a disadvantage of known circuit arrangements is that they are susceptible to errors resulting from noise and/or drift.
An object of the invention is an improved electrical circuit arrangement for producing an output signal dependent on the root mean square value of an input signal.
A more specific object of the invention is such a circuit arrangement which is capable of high accuracy by correcting for errors due to noise and/or drift.
A further object of the invention is an improved electrical multiplying circuit which may be used as the squaring circuit in a circuit arrangement for producing the RMS value of an input signal, though it is not limited to such application and may be used in other applications.